Computing the log concave NPMLE for interval censored data

In analyzing interval censored data, a non-parametric estimator is often desired due to difficulties in assessing model fits. Because of this, the non-parametric maximum likelihood estimator (NPMLE) is often the default estimator. However, the estimates for values of interest of the survival function, such as the quantiles, have very large standard errors due to the jagged form of the estimator. By forcing the estimator to be constrained to the class of log concave functions, the estimator is ensured to have a smooth survival estimate which has much better operating characteristics than the unconstrained NPMLE, without needing to specify a parametric family or smoothing parameter. In this paper, we first prove that the likelihood can be maximized under a finite set of parameters under mild conditions, although the log likelihood function is not strictly concave. We then present an efficient algorithm for computing a local maximum of the likelihood function. Using our fast new algorithm, we present evidence from simulated current status data suggesting that the rate of convergence of the log-concave estimator is faster (between \(n^{2/5}\) and \(n^{1/2}\)) than the unconstrained NPMLE (between \(n^{1/3}\) and \(n^{1/2}\)).     

Managing The Lactating Body: The Breast-Feeding Project and Privileged Motherhood

Drawing on interviews with twenty-five mostly white, educated, work-force experienced and class-privileged mothers, this paper explores how these women construct the lactating body as a carefully managed site and breast-feeding as a project—a task to be researched, planned, implemented, and assessed, with reliance on expert knowledge, professional advice, and consumption. The framing of breast-feeding as a project contrasts with the emphases on pleasure, embodied subjectivity, relationality, and empowerment that characterizes much of the recent breast-feeding literature across the humanities and social sciences. I argue that the project frame sheds light on the amount of work and self-discipline involved in compliance with broader middle-class mothering standards set in the consumerist, technological, medicalized, and professionalized contexts that shape parenting in late capitalist America.

Myths of Women and Their Reflection in a Therapy Group

One essential dilemma for modern clinical social work involves the relationship between the processes taking place inside the self and the social, cultural, and political developments affecting a person from the outside. The group-analysis approach focuses on four levels of relationships and communication within the group, among others a primordial level of shared myths, archetypical images, and the collective unconscious as an important component of psychotherapy. This article describes group-analysis therapy with women, analyzing a therapeutic process that used social myths to explore the formative institutionalization processes participants had undergone, thereby expanding themselves, growing, and changing.

Passing Encounters East and West: Comparing Japanese and American Pedestrian Interactions

This study examined the microinteractions of pedestrians in Japan and in the United States as they walked past a confederate. Specifically, the effects of culture, condition (avoid, look-only, and look plus smile) and sex of confederate on glances, smiles, nods, and greetings by passing pedestrians were examined in a field study on over 1000 participants. The hypotheses of (1) lower responsiveness in Japanese pedestrians than in American pedestrians and (2) increased responsiveness as a function of condition were supported in a series of log-linear analyses of pedestrian glances, smiles, nods, and greetings. Both of these main effects were, however, qualified by Culture X Condition interactions on smiles, nods, and greetings, with the large condition effects present in the American pedestrians, but absent in the Japanese pedestrians. The results are discussed in terms of the functions of glances, smiles, nods, and greetings in these brief encounters and how differing cultural norms affect Japanese and American responsiveness. Finally, the limitations of this study and the broader utility of this research paradigm are discussed.

Injunctive Norms and Problem Gambling among College Students

Two studies examined the relationships among injunctive norms and college student gambling. In study 1 we evaluated the accuracy of perceptions of other students’ approval of gambling and the relationship between perceived approval and gambling behavior. In study 2 we evaluated gambling behavior as a function of perceptions of approval of other students, friends, and family. In study 1, which included 2524 college students, perceptions of other students’ approval of gambling were found to be overestimated and were negatively associated with gambling behavior. The results of study 2, which included 565 college students, replicated the findings of study 1 and revealed positive associations between gambling behavior and perceived approval of friends and family. Results highlight the complexity of injunctive norms and the importance of considering the reference group (e.g., peers, friends, family members) in their evaluation. Results also encourage caution in considering the incorporation of injunctive norms in prevention and intervention approaches.     

Lessons from the Grey Area: A Closer Inspection of At-risk Gamblers

The study takes a closer look at at-risk gamblers, with the objective to see how they differ from no-risk gamblers. The data comes from a national gambling survey in 2002, and the age group is 15–74 years. The sample consists of 4188 current gamblers with no current gambling problems or pathology. The analysis includes cross-tabulations and a logistic regression. The results show that at-risk gamblers differed substantially from no-risk gamblers in terms of demographic characteristics, gambling behaviour and the presence of other assumed risk factors. Demographic segments with a higher risk of falling into the at-risk group are men, young people, divorced or single people, and non-western immigrants. Furthermore, gambling problems in the family, beginners luck and misconceptions about winning chances significantly increased the odds for at-risk gambling. The study concludes that at-risk gamblers deserve more attention from research, that their similarity with problem gamblers increases the likelihood that many of them will eventually develop a gambling problem, and that their tendency to be superstitious about winning chances might be exploited in preventive work.     

Gambling and Alcohol Use: Trends in the State of New Mexico from 1996–1998

Alcohol consumption and its relationship to gambling was examined in a statewide New Mexico survey in 1996 and 1998. Data regarding both drinking habits and gambling behavior were obtained from a stratified random sample of the adult population (N = 2674) across the entire State of New Mexico via phone survey. These surveys were carried out shortly after a period when New Mexico experienced an initial surge in the legalized gaming industry. Fifty-seven percent of survey respondents reported drinking in the past month, while 43.1% reported no drinking in the past 30 days. Results show that while the number of days in the past 30 that a person drinks is significantly correlated with some types of gambling behavior (e.g., in 1998, drinking more days was associated with more card gambling and sports gambling), it is the amount of alcohol consumed per occasion that is associated with more gambling behavior. For example, in both 1996 and 1998, drinking more per occasion was associated with more sports betting, dice gambling, number/lottery gambling, gambling using machines, and paper game gambling (e.g., pull tabs, punchboard). These results suggest that problem gambling behavior is not affected as much by the number of occasions on which one consumes alcohol, as by the amount of alcohol consumed per occasion.     

Gambling Behavior of Student-Athletes and a Student Cohort: What are the Odds?

This study investigated the prevalence of gambling, gambling related NCAA violations, and disordered gambling in student-athletes (n = 736) with a comparison cohort of students (n = 1,071) at four universities. Student-athletes reported similar rates of gambling frequency, use of a bookmaker, and disordered gambling as students. After accounting for demographic differences, student-athletes were less likely to engage in sports wagering than students. Several risk factors for disordered gambling were identified, including being male and reporting at least one parent with a history of gambling problems. These findings suggest that problems associated with gambling are a university-wide issue with student-athletes meriting additional attention because of implications for the integrity of intercollegiate sports. Improved prevention and intervention efforts for collegiate gambling are recommended.     

Full of Sound and Fury,Signifying Something: The Impact of Autonomic Arousal on EGM Gambling

An experiment was conducted to observe the influence of autonomic arousal on subsequent gambling behavior. Thirty-seven male and 32 female regular Electronic Gaming Machine (EGM) players were recruited through newspaper advertisements. Participants were randomly assigned to either: (1) a control condition, or (2) an experimental condition that introduced a loud white-noise event (80 db) at fixed 120 s intervals throughout the 5-min EGM gambling session. Galvanic Skin Response (GSR) measurements showed that the manipulation was successful in elevating autonomic arousal. The results showed differences in behavioral response to the manipulation based on prior experience with gambling problems. Persons with many gambling problems had lower average bet-sizes in the white-noise condition compared to the control, while those with few or no problems had higher average bet-sizes. The results suggest that arousal may provide different signals to gamblers with few versus many problems. Gamblers with many problems may interpret their arousal as a sign that they will soon lose money, while gamblers with few or no problems may associate feelings of arousal exclusively with winning.